1. Field of the Invention
This invention relates to a sheet feeding apparatus for feeding sheets such as original documents and to a sheet feeding method.
2. Description of Related Art
In printers, photocopiers, and facsimile machines, sheet feeding apparatuses are widely used these days to feed, sheet by sheet, original documents or recording sheets set as multiple sheets. In such a sheet feeding apparatus, a pickup roller feeds sheets set on a feeding tray; the sheets are separately fed one by one in rotating a feed roller while a separating member pushes the sheets to the feed roller; the sheet is fed by another feed roller disposed on a downstream side of the feed roller in a sheet feeding direction.
Such a sheet feeding apparatus may use a retard separation method in which sheets are separated and fed by the feed roller and a retard roller pushing the sheets toward the feed roller and rotating in the reverse direction to the sheet feeding direction. With such a retard separation method, however, if a user pushes sheets 600 too much when the sheets are set on a feeding tray, and as shown in FIG. 49, if the sheets are too much pushed into a separating nip of the feed roller 601 and the retard roller 602, the sheets cannot be separated well and may be fed doubly.